This application claims the priority benefit of Taiwan application Ser. No. 90131288, filed Dec. 18, 2001.
1. Field of Invention
The present invention relates to a package with cooling element therein. More particularly, the present invention relates to a multi-chip package with one or more cooling elements therein.
2. Description of Related Art
In this information explosion era, electronic products are used everywhere. Due to the rapid progress in the electronic industry, innovative multi-functional personalized electronic products are come out in the market almost daily. Most electronic products are designed with the least material, the smallest dimensions and the least weight in mind. Despite the fast development of powerful miniaturized electronic products, cooling is still a major problem.
To reduce size and weight and increase functional capacity of electronic products, more than one chip is often embedded inside a single package. FIG. 1 is a schematic cross-sectional view of a multi-chip module (MCM). As shown in FIG. 1, the multi-chip module 100 includes a plurality of chips 140, a substrate 110, a plurality of conductive wires 150, a plurality of solder balls 190 and packaging material 180 for enclosing the chips 140 and wires 150. The substrate 110 has a front surface 112 and a back surface 122. The front surface 112 of the substrate 110 also has a plurality of die pads 114 and a plurality of wire contacts 116. The wire contacts are positioned on the front surface 112 around the die pads 114. The substrate further includes a plurality of solder ball contacts 124 on the back surface 122. Each chip 140 has an active surface 142 and a back surface 148. The active surface 142 of the chip 140 further includes a plurality of bonding pads 144. The back surface 148 of the chip 140 is attached to the die pad 114 of the substrate 110. One end of each conductive wire 150 is in electrical contact with a bonding pad 144 while the other end of the conductive wire 150 is in electrical contact with the wire contact 116. The packaging material 180 encloses the substrate 110, the chips 140 and the conductive wires 150. The solder balls 190 are attached to the respective solder ball contacts 124.
In the aforementioned multi-chip module 100, all chips 140 are embedded inside the packaging material 180. Since each chip contributes some heat to the package during operation, the tight packaging of chips 140 inside the module may lead to considerable heat dissipation problem relative to a single chip package. If the heat is not channeled away fast enough, the entire module may overheat resulting in chip malfunction. Hence, increasing heat-dissipating capacity is always a central issue in the production of multi-chip modules.
Accordingly, one object of the present invention is to provide a multi-chip package with embedded cooling elements for rapidly dissipating heat generated by various chips away from the package.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a multi-chip package having one or more embedded cooling elements. The multi-chip package includes a substrate, a plurality of chips, at least one cooling element, a plurality of solder balls and packaging material. The substrate has a front surface and a corresponding back surface. The chips are attached to the front surface of the substrate and are electrically connected to the substrate. The cooling element is attached to at least one of the chips. The cooling element is fastened to the chip through thermal conductive glue. The solder balls are attached to the back surface of the substrate. The packaging material encloses the substrate, the chips and the cooling elements. According to the embodiment of this invention, a portion of the cooling element may be exposed by the packaging material or entirely embedded within the packaging material.
This invention also provides a second multi-chip package having one or more embedded cooling elements. The multi-chip package includes a lead frame, at least one first chip, at least one second chip and at least one cooling element and packaging material. The lead frame includes a die pad and a plurality of leads. The leads surround the die pad. The die pad has a die pad surface that corresponds to the backside of a chip. Each lead is further divided into an inner lead section and an outer lead section. The first chip is attached to the front surface of the die pad and electrically connected to some of leads. The second chip is attached to the back surface of the die pad and electrically connected to some other leads. The cooling element is attached to the upper surface of the first chip or the second chip. The cooling elements are bonded to the upper surface of the chip through thermal conductive glue. The packaging material encloses the die pad, the first chip, the second chip, the inner lead sections and the cooling elements. The outer lead sections of the leads are exposed. According to the embodiment of this invention, a portion of the cooling element may be exposed by the packaging material or entirely embedded within the packaging material.
Each multi-chip package encloses at least two chips. Hence, the package has considerable data processing power to meet future developmental demands. Moreover, the placement of cooling elements over all or some of the chips increases the heat-dissipating power of the package and reduces chip failure.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.